Valve cooling means



Dec. 22, 1936. w. J. SYMONS 2,065,106

VALVE COOLING MEANS Filed Feb. 15, 1955 2 Sheets-Sheet 1 INVENTOR: MY/(mz Liz/m Arromvm;

Dec. 22, 1936.

W. J. SYMONS VALVE COOLING MEANS Filed Feb. 15, 1933 2 Sheets-Sheet 2 INVENTOR. /z'llzkzm @1770;

ATTORNEYS.

Patented Dec. 22, 1936 PATENT OFFICE VALVE COOLING MEANS William J. Symons, West Los Angeles, Calif.

Application Februaryl3, 1933, Serial No. 656,427

- Claims. (Cl. 123-477) This invention relates to means for cooling the valves of an internal combustion engine, and refers particularly to the valves of an aeroplane motor.

To this end, the object of my invention is to provide means for directing a cooling fluid against I the valves of such engine, particularly the exhaust valves. A further object is to provide means for applying suificient pressure to the cooling fluid to overcome the pressure existing in the vicinity of such valve due to explosion expansion .of the engine fuel. Another object is to time the V delivery of the cooling fluid to coincide with the closing of the valve served. Another object is the provision of means for automatically maintaining the cooling fluid under uniform pressure. A further object is the provision of means for regulating the pressure of the cooling fluid to suit operating conditions.

These principal objects and the further novel and importantfeatures of the invention are hereinafter fully described and illustrated in the appended drawings, of which:

Fig. 1 is a cross sectional elevation through the center of one of the exhaust valves of an internal combustion engine;

Fig. 2 is a diagrammatic view illustrating means for supplying a cooling fluid under controlled, uniform pressure to the valve of Fig. 1; and

Figs. 3 and 4 illustrate modifications of such valve structure.

The devices for admitting cooling fluid to an exhaust valve are, in Fig. 1 shown to comprise a valve stem 1, terminating in a head 2 for registration with a valve seat 3, all as usual in practice. The valve stem is made hollow to provide a cylindrical chamber 4, into which the cooling fluid is delivered through one or more ports 5. From the bottom of this chamber, a plurality of passages 6 are shown diagonally and downwardly directed to discharge the cooling fluid along the upper surface of the valve head 2 and to the valve seat 3.

A conduit 1 is attached to the engine head and positioned to communicate with the port 5 of the valve stem through a port 8, which terminates in an annular chamber 9, encompassing the valve stem. The numeral [0 denotes an air compressor, pump or blower for delivering air under pressure through the valve stem. This may be an independent pressure means or, where a supercharger is employed, it may be found possible to obtain pressure fluid from the blower or compressor forming part of such supercharger.

. The operation of this simple device should be clear to anyone versed in the art. It is to be Y noted, that the ports 5 and 8 are in registration when the valve is closed, permitting a current of air to be forced through the valve stem and to impinge upon the valve head and seat. The

moment the valve commences to open, it is seen that the downward movement of the stem results in a closing of the ports 5 and 8, and a consequent disruption of the air supply. In this manner a considerable saving of cooling fluid is efiected, permitting employment of a much smaller pressure unit than would otherwise be required. A series of annular cooling fins l5 may conveniently be formed on the valve head to assist the cooling effect by increasing surface radiation.

The space within the valve stem, above the chamber 4, may be utilized to carry lubricants to the bearing. To this end, 'a'plug II is shown driven into the stem to form a separate chamber 12 for the proper lubricant, and this chamber is closed by a cap l3, in which a re-fllling plug I4 is shown seated.

Cooling of exhaust valves in aeroplane engines is most important, and the method above described is very eifective at high altitudes and at other places where the atmospheric temperature is low. But because atmospheric temperature ordinarily varies with altitude and with location, it is of great advantage to provide means for maintaining the cooling fluid at a suitable, predetermined degree of temperature. This may be accomplished in various ways, and the means now to be described in connection with Fig. 2 is illustrative of this feature.

The valve stem cooling elements may remain substantially as above described, but the conduit 1 is, in Fig. 2, shown to communicate, through a conduit 20, with a tank 2 i, and this tank is designed and proportioned to hold a supply of precooled substance, such as dry ice or liquid air. As the temperature of such cooling medium rises. an expansion of the substance takes place, resulting in suflicient pressure to force the cooling fluid through the valve. The pressure generated in response to this expansion is very considerable, and it may be found that additional compressing means, such as above referred to, may be entirely omitted.

On account of atmospheric temperature variations and consequent variations in the rate of expansion, it becomes necessary to insulate the generator tank, and this is here shown accomplished by enclosing the tank within a suitable casing 22,

made from or lined with heat insulating ma Employing such heat insulating casing,

terial. uniform expansion of the cooling medium is assured. As the normal rate of expansion of the cooling medium may not be found rapid enough to maintain'sufiicient pressure to continue to dewith a sleeve 24, encompassing the engine exhaust pipe 25, in spaced relation. Air within the space between the sleeve and the exhaust pipe becomes heated, and it rises through the tube 23 and the space between the generator tank 2| and the casing, thereby to increase the rate of expansion of the cooling medium. The heated air flnally wastes through a discharge orifice 32.

In the cover of the generator tank is shown mounted a capsular member 21, communicating with the outside air, but not with the interior of the tank. From this expansive member rises a stem 28 which, through the medium of a bell-' crank 29 and a rod 30, is connected to operate a valve 3|, of the tube 23. This mechanism is introduced to control the flow of heated air through the casing 22 in such manner, that the expansion of the cooling medium may be eifected at a predetermined, uniform rate. If, for example, the

heated air, circulating through the casing, causes more rapid expansion than required to maintain a desired pressure; a pressure increase sumcient to compress the capsular member 21 occurs within the tank, causing the stem 28 to rise, the bellcrank to rock on its pivot and to turn the valve 3| toward closing position; The flow of heated air is checked and the rate of expansion in this manner controlled.

It may be found, on the other hand, that the flow of heated air is not sufliciently rapid to accelerate the expansion of the cooling medium.

Where this is the case, I introduce means for increasing the flow of the heating fluid, and such means is here shown to consist in leading a conduit 33 from the exhaust orifice 32 of the casing to the exhaust pipe 25 of the engine, and in inclining this conduit, in the direction of flow within the exhaust pipe, sufliciently to cause a sucking action of the engine exhaust gases to draw the heated air rapidly through the casing.

, The lower end of the belicrank 29 is shown made with a slot 34, in which a clamping bolt, of the rod 30, is seated, and the purpose of this arrangement is to regulate the operation of the valve 3| to suit flying conditions. When more rapid expansion of the cooling medium is required, it is merely necessary to move this bolt upward in the slot and to'clamp it in position. Moving the rod downward, on the other hand, will have the effect of slowing down the expansion of the cooling medium.

To prevent unnecessary waste of the cooling medium, when the engine is temporarily out of service, it is well to provide a shut-oil valve 3 8, at a convenient point between the generator tank 2| and the valves of the engine. In addition to this, it may be found necessary to 'place a safety valve 39 in the generator tank or in the conduit leading therefrom, to prevent explosion, should the engine remain out of service long enough to build up considerable pressure within the tank. In the foregoing, my system of valve cooling is fully explained, but no attempt has been made to present a detailed design of a mechanically perfected device, in order not unnecessarily to complicate the disclosures.

It is well, however, to describe certain modifications in the valve structure. Such modifications are, in Fig. 3, shown to consist in leading the cooling fluid through the cylinder head wall directly to the valve head, and not through the valve stem, as hereinbefore described. The valve struction, except that-it is well to provide cooling fins 4|, to expedite heat radiation. The

' valve stem is here shown made with a cap 42, and

this can is made with a sleeve 43, which extends downward into an enlarged bore, or chamber 45 of the cylinder head, to a passage 44, which corresponds to the port 8 of Fig. 1. From the bottom of this chamber extend passages 46, for the cooling fluid, in direction of the flns 4| of the valve head. When the valve stem is depressed to open the valve, it is noticed that the sleeve 43 moves to cut ofi" communication between the port 44 and the chamber 45.

The structure of Fig. 4 differs from the foregoing in the means for controlling the conduit for the cooling fluid. In place of the sleeve 43, a plug 50 is shown-seated in an enlarged bore, or chamber 5| of the cylinder head, and this plug is perforated to form a bearing for the valve stem. A plurality of passages 52 lead from this chamber toward the valve head. As the plug 50 is stationary, no provision is made for cutting off the flow of the cooling fluid, but a check valve 53 is shown seated in the inlet port 54, to prevent back flow due to pressure of the exhaust gases, when the valve is open.

I claim:

1. In an internal combustion engine, the combination with the exhaust valves, of a receptacle for a substance capable of rapid expansion under atmospheric temperatures to generate a pressure fluid within said receptacle, a heat insulating casing encompassing said receptacle in spaced relation thereto, means for circulating a heat medium through the space between said receptacle and the said casing, means responsive to pressure variations within said receptacle for controlling the flow of said heat medium, and means for carrying fluid from said receptacle to the heads and seats of the said exhaust valves for cooling purposes.

2. In an internal combustion engine, the combination with the exhaust valves, of a receptacle for a substance capable of expansion in response -to the .said exhaust valves for cooling purposes.

3. In an internal combustion engine, the combination with the exhaust valves, of a receptacle for a substance capable of rapid expansion in response to temperat e variations to generate a pressure fluid within said receptacle, a heat insulating casing encompassing said receptacle in spaced relation thereto, a sleeve encompassing the engine exhaust pipe and spaced therefrom, a conduit connecting said sleeve with the space between the receptacle and its casing, a valve in said conduit, means responsive to pressure variations within ,said receptacle, and connections between the valve and the said pressure variation responsive means for controlling the said conduit valve. 7 WILLIAM J. SYMONS. 

